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Are you supposed to see when you close your eyes?

Closing your eyes is something we all do every day, often without even thinking about it. Yet behind this simple action lies a complex biological process that many of us take for granted. In this article, we’ll explore what really happens when you close your eyes, why you see or don’t see anything, and what it all means for vision and the human brain.

What Do You See When Your Eyes Are Closed?

When your eyes are open, light enters and stimulates the retina, allowing you to see. But when you close your eyelids, visible light is blocked. So does that mean you see nothing but blackness? Not quite.

Here’s a look at what you may see when your eyes are closed:

  • Blackness or dark gray – For many people, closing their eyes leads to a perception of black, dark gray, or even reddish hues.
  • Random flecks and patterns – Some people see random flecks of light or geometric patterns, almost like visual “noise.”
  • Phosphenes – These are sensations of light and color that aren’t caused by actual light entering your eye.
  • Mental imagery – You may visualize previous sights and scenes in your mind’s eye.
  • Hypnagogic hallucinations – In the transitional state between wakefulness and sleep, some people experience vivid, dreamlike hallucinations.

So in summary, while you may primarily see darkness, closing your eyes doesn’t necessarily lead to a blank visual field for most people.

What’s Going on Inside Your Eyes and Brain?

To understand why you see or don’t see anything when your eyes are closed, let’s take a look at what’s happening inside your eyes and brain:

Inside Your Eyes

Your retina contains two main types of light-sensitive cells:

  • Rods – Responsible for peripheral and night vision. Rods are sensitive to low light levels.
  • Cones – Provide central and color vision. Cones require brighter light to function.

When your eyes are open, rods and cones detect light and send signals to the brain through the optic nerve. But when your eyes close, rods and cones are no longer stimulated. Without stimulation, they’ll gradually stop sending signals to the brain.

Inside Your Brain

Visual information is processed in the occipital lobe at the back of your brain. When your eyes close, this region is no longer receiving direct sensory input. However, your brain remains active in other ways:

  • Your brain may construct mental imagery from memories.
  • Brain activity can stimulate the retina, creating phosphenes.
  • As you drift into sleep, your brain activity changes, which may lead to hypnagogic hallucinations.

In the absence of visual input, your brain doesn’t simply shut down. Internally generated visual phenomena arise instead.

Why Do You Sometimes See Light Patterns?

Seeing faint geometric patterns, specks of light, or phosphenes when your eyes are closed happens due to physiological processes in your eyes and brain:

Mechanical Pressure

Rubbing your closed eyelids can stimulate your retina through mechanical pressure. This pressure on the retina triggers it to send signals to the brain, creating a temporary perception of patterns or light.

Cortical Hyperexcitability

Increased excitability levels in the visual cortex can make people more susceptible to phosphenes when the eyes are closed. Anxiety, migraine, stroke, and use of psychedelic drugs are linked to cortical hyperexcitability.

Retinal Noise

The retina produces background electrical noise in rods and cones even without light exposure. This noise is usually drowned out by normal visual processing when your eyes are open. But when closed, the noise can translate into random light patterns.

How Does Mental Imagery Play a Role?

Beyond random phosphine patterns, some people can consciously visualize scenes, objects, and past sights in their mind’s eye when their eyes are closed. This ability to voluntarily generate mental imagery utilizes the brain’s visual processing system in the absence of external stimuli.

Brain imaging studies show that visualizing something in your mind’s eye activates similar brain regions as actually seeing that thing. Parts of the occipital, parietal and frontal lobes light up with both visualization and observation.

When visualizing with eyes closed, brain activation is lower compared to observing with eyes open. But the overall patterns are remarkably similar, illustrating how mental imagery relies on the same neural architecture as vision.

Why Do You Sometimes Hallucinate Before Sleep?

As you’re falling asleep, you may transition through brief periods of wakeful-dreaming known as hypnagogia. During these transitions, some people experience vivid auditory, visual, and sensory hallucinations known as hypnagogic hallucinations.

Hypnagogic hallucinations occur during Stage 1 sleep as your brain activity changes. During this stage, parts of your brain that support imagery, association, and visual memory become more active. But regions that help you orient yourself and provide context are less active.

This combination can result in strange, vivid hallucinations that feel real. The lack of orienting context explains why hypnagogic hallucinations are often more bizarre than regular dreaming.

How Does Eye Closure Impact Circadian Rhythms?

Closing your eyes doesn’t just change visual perception – it can influence circadian rhythms too. Circadian rhythms are 24-hour cycles governing functions like sleep, hormones, body temperature, and metabolism.

Light exposure plays a key role in setting and maintaining healthy circadian phase and alignment. Since eye closure blocks out light, it can shift circadian timing over time, especially if done consistently before bedtime.

Eye closure may communicate “time for sleep” to the brain. Studies show eye masks that block light can advance melatonin release and make it easier to fall asleep.

Effects of Closing Eyes on Circadian Rhythms

  • Can increase melatonin levels
  • May shift circadian phase earlier
  • Contributes to lower core body temperature before bed
  • Signals the brain to prepare for sleep

So closing your eyes doesn’t just change what you see – it may help cue your body’s sleep and wake cycles too.

Health Benefits of Eye Closure and Darkness

Closing your eyes has a range of evidenced-based health benefits beyond potentially improving sleep. Getting enough time with eyes closed and blocking out light can:

  • Increase growth hormone and melatonin release
  • Lower risk of nearsightedness in children
  • Improve mood disorders like depression
  • Lessen migraine pain and visual discomfort
  • Provide mental relaxation and contentment

Given these benefits, getting more time with your eyes closed even during waking hours may promote health. Yoga Nidra and other mind-body practices incorporate intentional eye closure for these reasons.

When to Seek Help for Visual Disturbances

In most cases, visual phenomena when closing your eyes are harmless quirks of the visual system. But occasionally, they may indicate an underlying medical condition requiring treatment, such as:

  • Eye disorders – Floaters, flashing lights, or shadows in your peripheral vision could signal retinal detachment, uveitis, or glaucoma.
  • Migraines – Visual auras and seeing zigzag lines may precede migraine headaches.
  • Epilepsy – Flashing lights when eyes are closed can be a seizure symptom.
  • Stroke – Loss of vision or patterns of light may indicate stroke-related visual disturbance.

See your doctor promptly if new visual symptoms arise, especially if accompanied by other signs of medical illness. Early diagnosis and treatment can lead to better outcomes.

In Summary

Closing your eyes may seem trivial, but the effects on visual perception, circadian rhythms, and brain function are complex. What you see with eyes closed ranges from blackness to phosphenes to mental imagery as the brain adapts to loss of stimuli. Getting enough time with eyes closed promotes health, but be sure to discuss any new symptoms with your doctor.

So the next time you close your eyes, take a moment to observe what happens in your visual field. Just don’t drift off to sleep too quickly!